In recent years, personal computers, each including a High-Definition Multimedia Interface (HDMI) connector, have come into use in increasing numbers. HDMI is an interface standard that enables one cable to transmit both video signals and audio signals. Any user of a notebook personal computer with an HDMI connector can therefore enjoy viewing, on a large screen, any high-definition TV program received through the HDMI connector and played back by the personal computer.
As in this case of connecting a personal computer and a television receiver to each other, a plurality of electronic apparatuses, each including the function of displaying images and the function of outputting audio data, are now connected and used in combination on more and more occasions. Hence, various methods of appropriately setting the apparatuses, to which video signals and audio signals should be output, have hitherto been proposed. (See, for example, Jpn. Pat. Appln. KOKAI Publication No. 2009-44253.)
If a television receiver is connected to, for example, a personal computer, images may be displayed on the screen of only one of these apparatuses, or on the screens of both apparatuses. Two methods of displaying images on both apparatuses are available. One is the clone display method that displays the same image on the screens of both apparatuses at the same time. The other is the multi-display method that displays a part of an image at one apparatus and the other part of the image on the other apparatus. In the multi-display method, one apparatus is primary, and the other is secondary. In the multi-display disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2009-44253, for example, the audio output is controlled, causing the primary apparatus to produce audio.
In the multi-display method, however, the audio data will inevitably output at the primary apparatus, not at the secondary apparatus which the user keeps his or her eyes on, if the secondary apparatus displays the window of a software item (application program) that is important to the user.